Gravure or letterpress cylinder engraving



May 25, 1954 T. HOMMEL GRAVURE OR LETTERPRESS CYLINDER ENGRAVING 2 Sheets-Sheet 1 Filed March 18 1950 FIG 1.

INVENTOR HOMMEL THEODORE ATTORNEY y 5, 1954 T. HOMMEL GRAVURE OR LETTERPRESS CYLINDER ENGRAVING 2 Sheets-Sheet 2 Filed March 18 1950 INVENTOR.

THEODORE HOMMEL ATTORNEY Patented May 25, 1954 a-tvaies GRAVURE QRLETTERPRESS omND-En ENGRAVING Thssdorc fi n s Webster G ve M a sisn to Universal Mat a qonporation ofDelaware ApplicationrMarch 51-8, 1950, Serial No. 150,527

.5 slam 1 this invention-relates in general to certain new and ,useful improvements :in means and methods of gravureor letterpress cylinderengraying.

:Gravure a or :letterpress cylinders .are ordinari y engraved by applying a.photosensitive;film-;to the cylinder surface and exposing itto light through a so=called negative which .is held tightly gtherearound. it .is essential that the negative be :held very tightly against the cylinder surface during exposure and this is usually accomplished by applying suction along theedgesof .the negatives to draw all the air from beneath the negative At the present time such suction is applied by relatively-complicated, expensive means and frequently the results are not wholly satisfactory.

It is,-therefore, the primary objectof the-pres.- ent invention to provide methods and means for applying suction to a negative so that the latter is securely and tightly held down against the surface of a gravure or letter-presscyli-nder simply and efiiciently.

Itis another object of the .present invention to provide methods -and-means of the type stated which are simple, inexpensive and can be employed ina quick, time-savingmanner.

it is a further object of the -present' invention to provide methods and means of the type stated which may bereadily employed f0l cylinders of various-lengths-and diameters without necessitating extensive equipment changes and set-ups.

And with the above and other objects in "View, my invention'resides in-the novel*features-of forin, construction, arrangement, and combination of parts presently described and-pointed out in the claims.

inthe accompanying drawings =62 sheets) Figure '1 is a side elevational'view of a cylinder step-up machine embodying the presentfinvention;

Figure 2 is a perspective view of "the edgesealing' strip-forming a part of thepresenttion;

Figure 3'is a vertical seetionalview taken along line 3 3 of Figure *1;

'Figure 4 is a fragmental sectional view taken along line 44 of Figure 3;

Figure 5jisa-transverse sectional view taken along :line '5-6 of "Figure 2;

"Figure 6 is a transverse sectional View of a modified form of cylinder step-up machine embodying the present invention.

Figure 7 is a sectional view taken along line 1- 1 of Figure 6; and

vFi ur .8 i .airasnisnta y sectiona ie taken along line ib-8 of Figure '7.

R fe rin ow i mg efs siai and' y its mass hara r to t e drawing Wh Qh i ls w s a p a ti a em odim nt the Presen i te tion A designates 1a 0 unde s e -1 ma hine -9. the yp moreiull di los d and esc ibe -,n. o-- pendi ppl ca ion. Se ia 634 i si on May 19. .6 n w Paten iNP- 254 2 ssued Ap il :3 1 h mac ne A som ri s a it I havin s de w ys 12 o lsh tab y Su po n a pair f spac d para le mandr -ho de s :3, A,

hro h whic i :m a aifly mou ted in .ma i 5. At its one nd the mandrel 3 is r ta h mounted n an intermedia e hea in 6 a d a its uter end in a uts ib rins ii n hes a s between ,the bearings 15, l, the mandrel is rigidly provided with .a ace pl :8, havi a p u a it of un formly spaced ape turesfinadapted fo 2 ceivins th ton e po tion :ill of a pr n pressed p s t nin p n ili-By pul ns fthe in 4; ioutwardlyto. disengaeeith n ue por ion l9 t ere f, the platermayiberotated fa -predetermined number of degrees untiLthe tongue-portion H3 will drop back into .the next aperture s. :By this means the mandrel ;5 may be progressively rotated step by step throughaccurate fractional portions of .a complete rotation.

Carried by,the mandrelz5,.-on thatportion Oil-13S length which :is located between the mandrelholders 3, 4, is a gravure cylinder C, vgru'oyided upon its outer face Witha photosensitive layer or film l2. Operatively mounted on the base I, for adjustmentinto positionadjacent to :the cyls inder C on opposite sidesthereof, aresuction bars I3 adapted to fit lengthwise over and againstgthe longitudinal edges of a film-negative which is wrapped partially around the cylinder .C, as ibes t seen in Figure 3. The suction bars 13 are con.- nected by conventionalrubber tubes i4 .=t;o a.- oonventional vacuum pump, the latter not being shown. Provided for-cowoperation with the cyls inder C andthe suction bars 13, is amend-sealing strip S,;coznprising.a long flat section it formed of tough paper fabric or any other,similar rnateria1 provided uponits upper face with a margi nally registering adhesivelly bonded cover strip li'l. Sealed between the section .16, I1, arelongitus dinally e endin spa e para c r mem ers l8, IS. 'The strip S is provided at unifo nl y spaced intervals alongits inner margin-2G withia series of narrow preferably rectangular,-indentations or slots 2|, all preferably of uniform size and shape. The slots ;2l each cut across and, in effect, sever the cord l ebut terminate in the space between such cord l9 and cord i8, so that the latter is, in efiect, unbroken throughout its length,

In use two lengths of end-sealing stri S are cut off, each being of a length approximately equaling the transverse width of the film negative N. These two lengths are laid around the cylinder with the cover section I! in upwardly or outwardly presented position and in such position as to partially underlie the opposite transverse margins of the film-negative N when the latter is wrapped around the cylinder C preparatory to exposure. It will be noted that the ridges formed by the cords l3, l9 will be in contact with the under face of the film-negative N, as shown in Figure 4. The ends of the strips S will extend into the suction channels 22 of the suction bars I3. It will be noted, by reference to Figure 4, that in this operative position there will be a very minute but continuous peripheral channel 23, designed by the cords l8, l9 and extending along the under face of the film-negative N. This so-called channel 23 will be in communication with the entire under face of the film-negative N through the several slots 2!, so that the vacuum pump, operating through the suction bars l3 and the channels 22 thereof, will be enabled to draw the air out from between the sensitized surface l2 of the cylinder and the under face of the film-negative N, thereby permitting the film-negative N to be forced into tight, uniform and unwrinkled contact so that a highly accurate exposure may be made.

It has been found that the sealing strip or element above described is extremely efiioient and it is, at the same time, exceedingly economical and simple to use. Sealing strips constructed in accordance with the present invention may be made up in long continuous lengths upon rolls of any suitable size and may be out oil in various lengths for each particular job, depending upon the size of the particular negative which is being exposed. It has been found that where a certain size of negative is being used repeatedly the sealing strips may be used over and over.

It is also possible to provide a modified meth- 0d of superimposition of the negative upon a gravure cylinder as shown in Figures 6 to 8 inl elusive wherein designates a mandrel substantially identical with the previously described mandrel. 5. Mounted on the mandrel 5 is a gravure cylinder C provided on its outer face with a photosensitive film I2. Operatively mounted adjacent the mandrel 5 for co-operation therewith are hold-down bars 24 provided with longitudinally extending rubber pads 25 adapted to rest against the longitudinal edges of a film-negative N as it lies wrapped around the cylinder 0. Also wrapped around the cylinder C so as to underlie each of the transverse ends of the negative N are sealing strips S, each being of such length as to terminate at its ends a substantial distance inwardly from the longitudinal margins of the film negative N. Also applied to the cylinder C so as to underlie, and project outwardly along, the longitudinal margins of the film negative N are sections of tape 26 of approximately the same thickness as the sealing strips S. it should be noted that the sections of tape 26 extend across the ends of "the sealing strips 5 and in effect form end closures across the ends of the suction channels 23 formed along the under-face of the film negative N.

Provided for co-operation with the mandrel 5' and film negative N, are two semi-circular suction manifolds 2'! connected by a suitable fitting 28 to a suction line 29. Formed preferably integrally with each manifold 21 are five radially inwardly projecting suction cups 30.

The film negative N is punctured in five places conforming to the positions of the suction cups 3% to provide apertures 3| communicating with the suction channels 23. The suction cups 30 are then set down over the apertures 3| as shown in Figure 6 and suction applied. It has been found that a smooth, highly satisfactory superimposition of the film negative N upon the cylinder C can thus be obtained and the film negative N will tend to slip down slightly over the sections of tape 26 as the suction is first applied, to adjust for slight variations in circumferential dimensions as it conforms to the cylinder C. Once fully in place, the film negative N will, of course, be held securely unmovably, and without any creases or wrinkles.

It should be understood that changes and modifications in the form, construction, arrangement and combination of the several parts of the means and methods of gravure or letterpress cylinder engraving may be made and substituted for those herein shown and described without departing from the nature and principle of my invention.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A photoengraving machine comprising means for supporting a photo-sensitized element, a film-negative superimposed upon said element, a tape having spaced parallel raised portions adapted for disposition under the margins of the film-negative between the under face of the filmnegative and the outer face of the photosensitized element, said film-negative being provided with a plurality of small apertures opening into the space between the film-negative and said element, and means communicating with the sealed-off space between the film-negative and said element through said apertures for exhausting the air therefrom whereby to produce intimate contact between the film-negative and said elements.

2. A photoengraving machine comprising means for supporting a photo-sensitized element, a film-negative superimposed upon said element, a tape having spaced parallel raised portions adapted for disposition under the margins of the film-negative between the under race of the filmnegative and the outer face or the photosensitized element, said film-negative being provided with a plurality of small apertures opening into the space between the film-negative and said element, means communicating with the sealed-off space between the film-negative and said element through said apertures for exhausting the air therefrom whereby to produce intimate contact between the film-negative and said elements, and swingable means adapted to rest against at least one margin of the film-negative and press it snugly against the photo-sensitized element.

3. A photoengraving machine comprising means for supporting a photosensitized element, a film-negative superimposed upon said element, a tape having spaced parallel raised portions adapted for disposition under the margins of the film-negative between the under race of the filmnegative and the outer face of the photosensitized element, said film-negative being provided with a plurality of small apertures opening into the space between the film-negative and said element, means communicating with the sealed-01f space between the film-negative and said element through said apertures for exhausting the air therefrom whereby to produce intimate contact between the film-negative and said elements, and a swingable bar adapted to rest against a margin 01 the film-negative and press it snugly against the photo-sensitized element.

4. A photoengraving machine comprising a mandrel, a, photo-sensitized cylinder operatively mounted on the mandrel, a flexible film-negative disposed upon and extending in overlying relation around the photosensitized cylinder, a semicircular suction manifold operatively mounted adjacent to the mandrel in outwardly spaced concentric relation to the photosensitized cylinder, and a plurality of flexible off-takes connected to the suction manifold and extending radially inward toward the film-negative, said off-takes each terminating in a suction cup adapted to be disposed upon the outer surface of the film-negative when the latter is operatively mounted upon the cylinder.

5. A photoengraving machine comprising a mandrel, a photo-sensitized cylinder operatively mounted on the mandrel, a flexible film-negative disposed upon and extending in overlying relation around the photosensitized cylinder, a semicircular suction manifold operatively mounted adjacent to the mandrel in outwardly spaced concentric relation to the photosensitized cylinder, a plurality of flexible oflE-takes connected to the suction manifold and extending radially inwardly toward the film-negative, said off-takes each terminating in a suction cup adapted to be disposed upon the outer surface of the film-negative when the latter is operatively mounted upon the cylinder, and relatively thin tape-like elements adapted to be placed upon the photosensitized surface of the cylinder to frame the area in which the exposure is to be made and underlie the margins of the film-negative thereby sealing the space between the photo-sensitized surface and the film-negative in the area of the exposure to permit substantially complete evacuation of said space.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,267,646 Gorig Dec. 23, 1941 2,398,303 Glassey Apr. 9, 1946 2,408,310 Hassler Sept. 24, 1946 2,417,496 Huebner Mar. 18, 1947 2,547,527 Hommel Apr. 3, 1951 FOREIGN PATENTS Number Country Date 466,675 Germany Oct. 10, 1928 528,304 Great Britain Oct. 25, 1940 

